Cornell Notes 2-4 What Are Graphs? November 2, 2011 Page 67

Linear and Non-Linear Graphs Linear graphs go in a straight line. They represent relationships with the formula y=kx k is the slope of the line. You can figure out slope by dividing change in y over change in x (10-5)/(2-1)=5/1=5

Non-Linear Graphs Non-linear graphs go in curves They usually have formulas like y=kx2

The Rectangle Method You can use the rectangle method to make predictions. Just find the key term on the axis, draw a straight line up to the graph, and another straight line to the other axis. If you need to, you can extend the graph in either direction to help make your prediction

Position vs Time Graphs In a position vs time graph, time is on the x and position on the y. If the line is linear, then the object graphed I moving at a constant speed If the line is non-linear, then the object’s speed is changing For constant speed, objects with greater speeds have steeper slopes

Slopes on PvT Graphs The slope on a PvT graph shows the speed of the object. To calculate slope, do the following Pick two points on the graph Subtract the y-values of the points, the point on the right going first (y2-y1) Subtract the x-values of the points, the point on the right going first (x2-x1) Divide the y’s by the x’s (Rise over run)

Example (120 - 60)  (80 - 40) = 60  20 = 3 cm/s Y Goes Up 20 X Goes Up 40 (120 - 60)  (80 - 40) = 60  20 = 3 cm/s